1. Field of the Invention
The present invention relates to an assembly structure of a drive shaft and a swash plate in a swash plate type compressor, and more particularly, to an assembly structure of a drive shaft and a swash plate in a swash plate type compressor capable of simplifying structure and reducing weight thereof by providing a pin-shaped assembly structure.
2. Description of the Prior Art
A general swash plate type compressor is widely used as a compressor of an air conditioner for a vehicle. In such a swash plate type compressor, a disc-shaped swash plate having a certain tilt angle is fixedly installed at a drive shaft for receiving power from an engine to be rotated by the drive shaft. Rotation of the swash plate reciprocates a plurality of pistons inserted into a plurality of cylinder bores formed in a cylinder block through the medium of shoes formed along a periphery of the swash plate, thereby sucking, compressing and discharging a coolant gas.
In particular, in recent times, a variable displacement swash plate type compressor has been developed. Here, a tilt angle of the swash plate is varied depending on a thermal load to control strokes of pistons to accomplish precise temperature control. At the same time, the tilt angle is continuously varied to reduce abrupt torque fluctuation of an engine caused by the compressor, thereby improving ride comfort of a vehicle.
An example of a typical variable displacement swash plate type compressor is disclosed in Korean Patent Registration No. 0386912 (hereinafter, referred to as “conventional art”), and the structure is shown in FIG. 1.
As shown, the conventional variable displacement swash plate type compressor includes a cylinder block 12 having a plurality of cylinder bores 12a parallelly formed in a longitudinal direction of an inner periphery thereof, a front housing 11 hermetically coupled to a front part of the cylinder block 12, and a rear housing 13 hermetically coupled to a rear part of the cylinder block 12 with a valve plate 14 interposed therebetween.
A swash plate chamber 15 is provided inside the front housing 11, and a drive shaft 16 is disposed to pass through the swash plate chamber 15. For this purpose, one end of the drive shaft 16 is rotatably supported at a center of the front housing 11 via a bearing, and the other end of the drive shaft 16 is rotatably supported in a center shaft hole of the cylinder block 12.
In addition, a swash plate 18 is installed at the drive shaft 16 to move along a hinge mechanism of a lug plate 17 and vary a tilt angle thereof.
Further, the rear housing 13 includes a discharge chamber 27 and a suction chamber 28, and the valve plate 14 interposed between the rear housing 13 and the cylinder block 12 has a discharge port 29 and a suction port 31 corresponding to each cylinder bore 12a. 
A suction valve 30 and a discharge valve 32 are installed at the suction port 31 and the discharge port 29 formed in the valve plate 14 to open and close the suction port 31 and the discharge port 29 using pressure variation according to reciprocation of the piston 20.
Meanwhile, the piston 20 includes a piston head 22 reciprocating along the cylinder bore 12a, and a piston neck 23 through which the swash plate 18 passes. In addition, a seat is formed at the neck 23 to accommodate a shoe 21 such that the swash plate 18 passes through the shoe 21.
According to the above constitution, rotation of the drive shaft 16 rotates the lug plate 17 and the swash plate 18, and the tilted swash plate 18 is rotated beyond the shoe 21 to straightly reciprocate the piston 20 along the cylinder bore 12a. 
However, since an assembly structure of a drive shaft and a swash plate of the conventional swash plate type compressor employs the lug plate 17 and a hinge structure 19 in order to transmit power between the drive shaft 16 and the swash plate 18 and prevent loosening therebetween, the assembly structure and the internal structure of the compressor are complicated and heavyweight.